build(deps): Bump testcontainersVersion in /chat-backend

Bumps `testcontainersVersion` from 1.17.6 to 1.19.3.

Updates `org.testcontainers:testcontainers` from 1.17.6 to 1.19.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.17.6...1.19.3)

Updates `org.testcontainers:junit-jupiter` from 1.17.6 to 1.19.3
- [Release notes](https://github.com/testcontainers/testcontainers-java/releases)
- [Changelog](https://github.com/testcontainers/testcontainers-java/blob/main/CHANGELOG.md)
- [Commits](testcontainers/testcontainers-java@1.17.6...1.19.3)

---
updated-dependencies:
- dependency-name: org.testcontainers:testcontainers
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.testcontainers:junit-jupiter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

chat-backend/build.gradle

@@ -8,7 +8,7 @@ plugins {
 }
 
 ext {
-	testcontainersVersion = '1.17.6'
+	testcontainersVersion = '1.19.3'
 	lombokVersion = '1.18.26'
 	keycloakVersion = '20.0.3'
 }